Appliance control knob



FIG. 1 is a front perspective view of the design of the appliance control knob;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view with the left side being a mirror image thereof; and,

FIG. 5 is a top plan view thereof.

The broken lines shown are for illustrative purposes only and form no part of the design claimed. 

The ornamental design for an appliance control knob, as shown and described. 